1. Field of the Invention
Aspects of the present invention relate to an organic light-emitting display device, and more particularly to an organic light-emitting display device wherein an IR drop (voltage drop) across first electrodes is prevented.
2. Description of the Related Art
Various flat panel display devices including passive matrix organic light-emitting display devices have recently been developed to meet the need for slimmer and larger-screen display devices. An example image display unit 20 of a passive matrix organic light-emitting display device is shown in FIG. 1.
Referring to FIG. 1, the image display unit 20 includes stripe-shaped first electrodes 21 extending in a Y direction, stripe-shaped second electrodes 22 extending in an X direction to cross the stripe-shaped first electrodes 21, and an intermediate layer 24 disposed between the first electrodes 21 and the second electrodes 22. As shown in FIG. 1, the intermediate layer 24 is disposed to cover the first electrodes 21; and, the second electrodes 22 are disposed on the intermediate layer 24. The intermediate layer 24 includes at least an emission layer in which holes combine with electrons to generate light. The first and second electrodes 21 and 22 intersect to form pixels, which are arranged to emit light and form images. The holes are supplied to the intermediate layer 24 from one of the first electrodes 21 and the second electrodes 22, and the electrons are supplied to the intermediate layer 24 by the other of the first electrodes 21 and the second electrodes 22.
As described in connection with FIG. 1, the passive matrix organic light-emitting display device includes stripe-shaped electrodes. Methods of forming stripe-shaped electrodes include a method using deposition on an entire surface and lithography, an ink jet printing method, a deposition method using a mask, and the like. However, the method using deposition on an entire surface and lithography involves complex processes, such as deposition, photoresist coating, patterning, and etching, etc. Furthermore, the intermediate layer 24 may be damaged during the formation of the stripe-shaped second electrodes 22, which are formed after and on the intermediate layer 24. In contrast, the ink jet printing method is time consuming when applied to a large area.
To address these and/or other problems, a method using a separator has been suggested. FIG. 2 is a sectional view schematically illustrating a portion of a conventional organic light-emitting display device in which second electrodes 22 are formed to be stripe-shaped using second electrode separators 31.
Referring to FIG. 2, stripe-shaped first electrodes 21 are formed on a substrate 10 using a conventional method to extend in a first direction, i.e., a Y direction. And, the second electrode separators 31 are formed to extend in a second direction, i.e., an X direction, and to cross the stripe-shaped first electrodes 21. Next, an intermediate layer 24 is formed to cover the first electrodes 21. Then, the second electrodes 22 are formed on the entire surface of the intermediate layer 24. During application of the intermediate layer 24 and the second electrodes 22, a portion 24a of the intermediate layer 24 and a portion 22a of the second electrodes 22 are formed on the second electrode separators 31. So, when forming the second electrodes 22 on the entire surface of the intermediate layer 24, a portion 22a, which is the same as the material used to form the second electrodes 22, is also deposited on the upper surface of the second electrode separators 31. As the portion 22a of the second electrodes 22 is physically separated from the second electrodes 22 by the height of the second electrode separators 31 and because the portion 22a does not contact the second electrodes 22, the second electrodes 22 are accordingly formed to be stripe-shaped. A portion of the intermediate layer 24 can also be formed by deposition and the material forming the intermediate layer 24 can be deposited on the upper surface of the second electrode separators 31 (referring to the portion 24a).
However, the stripe-shaped first electrodes 21 have a high electrical resistance when they are formed of a transparent material. In particular, the IR drop across the stripe-shaped first electrodes 21 increases as the size of a screen of the organic light-emitting display device and brightness are increased. Thus, organic light-emitting display devices suffer from problems such as increased power consumption and reduced life span.